CN113263163A

CN113263163A - Method for efficiently eliminating gas adsorbed on solid surface and application thereof

Info

Publication number: CN113263163A
Application number: CN202110469514.1A
Authority: CN
Inventors: 沈军; 邓胜涛
Original assignee: Shenzhen University
Current assignee: Shenzhen University
Priority date: 2021-04-28
Filing date: 2021-04-28
Publication date: 2021-08-17

Abstract

The invention discloses a method for eliminating gas adsorbed on the surface of a solid with high efficiency and application thereof, which utilizes a method for applying an energy source to the gas adsorbed on the surface of the solid to improve the kinetic energy of the gas, gas molecules are separated from the solid surfaces of a die cavity or a sheath and the like, the gas in the die cavity or the sheath can be quickly eliminated under the action of a vacuum pump, and the purpose of eliminating the gas adsorbed on the surface with high efficiency is achieved. The method of the invention can not only be applied to the common manufacturing process, but also have good effect when being applied to the manufacturing of extremely complex precision devices.

Description

Method for efficiently eliminating gas adsorbed on solid surface and application thereof

Technical Field

The invention relates to the technical field of manufacturing of precision devices or devices used in the field of tips, in particular to a method for efficiently eliminating adsorbed gas on a solid surface and application thereof.

Background

The precision device or the device used in the tip field puts higher requirements on the performance of the alloy material, and also puts higher requirements on the manufacturing precision, the complexity of the configuration and the like. Under the traction of application requirements, people develop various advanced materials and various advanced material preparation technologies, such as centrifugal casting, seepage casting, extrusion casting and the like, while developing different advanced materials, so that various advanced alloys and composite materials with the performance and the size meeting related application requirements are prepared. In addition to the various casting techniques described above, jacket extrusion is also a common method of preparing composite materials in industry.

The centrifugal casting method is a method in which an alloy liquid is poured into a preformed mold by centrifugal force generated by rotation during casting, thereby obtaining a desired cast product. A seepage casting method for preparing metal-base composite material includes such steps as putting additional phases (directional long fibres, block, spherical body, short fibres, foam block, etc) in mould, pouring molten alloy into mould by external force (gravity, pressure, etc), holding the temp for a certain time, filling the molten alloy in the gap between additional phases, cooling quickly to solidify the molten alloy, and solidifying the molten alloy to obtain the needed metal-base composite material, i.e. preparing three-dimensional dual-continuous-phase composite material, putting porous silicon carbide as skeleton in the cavity, infiltrating molten alloy into the continuous holes of skeleton, solidifying, and preparing composite material, the problem of a large number of micropores in the composite material is difficult to solve. The continuous porous material has extremely high specific surface area, rough microscopic surface and complex interconnected channel configuration, and the structural characteristics lead to the material to adsorb a large amount of gas molecules on one hand and lead to the difficulty in gas molecule diffusion caused by the channels with complex configuration on the other hand. The problem that gas is adsorbed on the surface of a porous material is generally solved by prolonging the vacuumizing time in a laboratory, but even if the composite material is prepared by adopting a long-time vacuumizing process, only a sample with a thin thickness can be prepared, because along with the increase of the thickness of the framework, gas molecules adsorbed on the middle part of the framework are difficult to effectively eliminate even if the composite material is vacuumized for a long time, so that a large number of holes are easy to appear in the middle of the prepared composite material. The extrusion casting method is characterized in that a molten alloy liquid is rapidly extruded into a placed die cavity by adopting a method similar to injection molding, and compared with the traditional casting method, the extrusion casting method has the capability of manufacturing a device with a complex configuration and a high-precision thin-wall part, and has the characteristics of high manufacturing efficiency, few subsequent processing steps and the like.

Compared with traditional alloys such as steel, aluminum alloy, titanium alloy and the like, the atomic arrangement of the bulk amorphous alloy is different from the three-dimensional periodic arrangement of atoms of the traditional crystalline alloy, but presents the characteristics of unique short-range order and long-range disorder, and the difference of the atomic arrangement modes makes the bulk amorphous alloy have a series of unique properties such as elastic limit of about 2%, high breaking strength, near-net forming capability and the like, particularly near-net forming capability, so that the capability avoids casting defects such as shrinkage cavities and the like formed in the solidification process of the traditional crystalline alloy on one hand, and ensures that a finished product can be obtained by almost no subsequent processing or only a small amount of subsequent processing of a bulk amorphous alloy sample on the other hand, and the bulk amorphous alloy has the advantages of energy conservation and high efficiency. In addition, thin-walled parts with complex configuration can be manufactured by using the bulk amorphous alloy, and the advantages enable the bulk amorphous alloy device manufacturing to be regarded as one member in green manufacturing industry. Until now, bulk amorphous alloy devices have been manufactured essentially by extrusion casting. The bulk amorphous alloy is widely applied to smart phones in the form of devices such as mobile phone outer frames, camera supports, hinges and the like, and is also concerned by high-grade wristwatch manufacturers, medical equipment manufacturers and the like. Besides the application in the civil field, the bulk amorphous alloy also gains a place in the application in the military industrial field, the depleted uranium armor-piercing bomb has extremely excellent performance, but the residual radiation can hurt the weapon user, in order to thoroughly eliminate the problem of the residual radiation of the depleted uranium armor-piercing bomb, Caltech is given to research the novel armor-piercing bomb capable of replacing the depleted uranium armor-piercing bomb, the composite armor-piercing bomb which is developed by the university based on the bulk amorphous alloy and has armor-piercing capability not output to the depleted uranium armor-piercing bomb is provided, and the influence of the residual radiation of the depleted uranium bomb is thoroughly eliminated on the premise of guaranteeing the combat performance.

In order to ensure the performance of the material and the precision of the device, whether centrifugal casting, seepage casting or extrusion casting is adopted, the casting process is often carried out in a vacuum environment, which means that a cavity of a mold needs to be pre-vacuumized before casting is carried out. Taking squeeze casting as an example, in the actual industrial production process, in order to ensure the production efficiency, the time of vacuumizing is not more than 5min, even controlled within 2min, micro-holes are often formed inside the manufactured device, the mechanical property of the device is seriously affected by the micro-holes, the product yield is reduced, and particularly when the device is a thin-wall part with a complex configuration, the micro-holes in the device are extremely difficult to eliminate, so that the product meeting the application requirements is difficult to produce. Although the vacuum degree in the mold cavity can be improved by prolonging the vacuumizing time under the laboratory condition, in some cases, even if the vacuumizing is carried out for a long time, the occurrence of holes in a sample is still difficult to avoid, for example, when a composite material is prepared, the holes are easily formed in the interior of the composite material. The holes lead to poor bonding property between the matrix and the second phase of the composite material, and further have adverse effect on the mechanical property of the composite material; and, when the second phase is a continuous porous material, only a sample with a small thickness can be prepared, because as the thickness of the porous material increases, even if the porous material is vacuumized for a long time, gas molecules adsorbed at the middle part of the porous material are difficult to be effectively eliminated, so that a large number of holes are easy to appear at the middle part of the prepared composite material. For example, chinese patent CN109280795A discloses a nano-micron SiC particle reinforced wear-resistant aluminum matrix composite and a preparation method thereof, wherein a squeeze casting method is used to cast molten aluminum alloy into a mold with a reinforcement precast block, but the pore defect still exists, which results in the performance reduction of the product. Thus, the problem of casting holes is prevalent, both in the laboratory and in the industry.

The extrusion of the sheath is a commonly used method for preparing materials in industry, block, fibrous or even powdery materials are put into a prefabricated sheath according to needs in advance, the sheath is sealed after vacuum pumping at room temperature, and then hot extrusion processing is carried out or hot isostatic pressing process is added and then hot extrusion processing is carried out. However, if more residual gas exists in the sheath or the sheath is not sealed tightly, the surface of the sheath after being extruded by an extruder can generate obvious bubbling phenomenon, so that the sample is scrapped. In a more serious situation, a small amount of gas is remained in the sheath, the composite bar is obtained after extrusion by an extruder, the bar has a normal appearance, any bubbling cannot be seen, but cracks penetrating the whole bar along a long fiber interface appear in the spindle, the penetrating cracks increase the difficulty of subsequent processing on one hand, and on the other hand, even if a final process link is completed, the performance of the obtained sample cannot meet the application requirements easily, so that the production waste is caused. The main problem still exists is that gas still exists after vacuum pumping, and the quality of the product is influenced. Effectively solve the hole problem, on the one hand can promote the performance of material or device, and on the other hand will help promoting the qualification rate of product, reduces the waste of the raw materials in the production process and the energy, makes green manufacturing genuine. Therefore, the elimination of holes in materials or devices is of great practical significance.

In summary, in order to make a profit, in the industry, production efficiency must be ensured during production, which directly results in a short evacuation time, causing a certain amount of gas molecules to be adsorbed on the surface of the mold cavity even after evacuation, and on the other hand, when manufacturing thin-walled parts with complex configurations, the problem of gas adsorption on the surface of the mold cavity becomes more serious because the complex configurations cause an increase in the surface area of the mold cavity and thus more gas molecules to be adsorbed, while the thin walls mean a narrowing of the pitch of the mold cavity, which causes a narrowing of the passage of the free gas molecules out of the cavity during evacuation, making it difficult to smoothly leave the mold cavity within a limited time. When the alloy melt is injected into the die cavity, the gas in the die cavity is wrapped in the alloy liquid, and when the alloy liquid is solidified, the gas is locked in the solid to become holes.

Therefore, finding the commonalities of the above problems and proposing effective solutions is of great significance to the improvement of material or device performance, the reduction of production energy consumption, etc., both in the industry and in the laboratory.

Disclosure of Invention

The invention provides a method for efficiently eliminating gas adsorbed on the surface of a solid, which can effectively eliminate gas adsorbed on the inner surface of a mold or the surface of a second phase of a composite material in the process of vacuumizing during precision casting or composite material preparation, solves the problem of holes in the prepared material or device, ensures the performance of the material or device, avoids the problem of sample performance reduction or product scrapping caused by gas adsorbed in a sheath in the sheath extrusion process, and improves the production efficiency.

Another object of the present invention is to provide a device for efficiently eliminating gas adsorbed on a solid surface.

It is still another object of the present invention to provide an application of the method for efficiently eliminating gas adsorbed on the surface of a solid.

The above purpose of the invention is realized by the following technical scheme:

a method for eliminating the adsorbed gas on the surface of solid in casting and/or extruding from jacket features that when the cavity of mould or jacket is vacuumized, the adsorbed gas on the surface of solid is energized to increase its kinetic energy and eliminate the adsorbed gas on the surface of solid.

The surfaces of the cavity of the die and the surfaces of the second phase and other solids used for preparing the composite material, which are used in the manufacturing technology of casting (such as common process methods of extrusion casting, seepage casting, centrifugal casting and the like) and/or sheath extrusion and the like, are adsorbed with gas molecules, van der Waals force is the fundamental cause of adsorption of gas molecules on solid surfaces, Van der Waals force is a ubiquitous interaction force between molecules, the force has the characteristics of non-orientation, no saturation, weak strength and the like, and the strength of the van der Waals force is very weak compared with the action strength of chemical bonds such as ionic bonds, covalent bonds and the like, the energy is usually less than 5kJ/mol, while the energy released when 1g of pure aluminum powder reacts with oxygen and is completely combusted is more than 30kJ, less energy is required to adequately drive the gas molecules adsorbed on the solid surface away from the solid surface. Gas adsorption on the surface of a solid is a general physical phenomenon, when the surface of a material has high roughness and large specific surface area, the gas adsorption capacity of the surface of the solid is enhanced, and a schematic diagram of gas molecules adsorbed on the surface of the solid in a microscopic state is shown in fig. 1.

The invention promotes the gas molecules adsorbed on the inner wall surface of the chamber to break loose of the constraint of van der waals force and leave the solid surface by improving the energy of the gas molecules, thereby achieving the purpose of efficiently eliminating the gas molecules adsorbed in the chamber in limited vacuum-pumping time or in a complex vacuum-pumping environment. This requires applying energy to the solid, and after turning on the energy source, the energy is transferred from the solid to the gas molecules adsorbed on the solid surface, and the rising of the energy promotes the gas molecules to leave the solid surface, and after applying the energy, the gas molecules adsorbed on the solid surface are schematically shown in fig. 2, and as can be seen from the comparison with fig. 1, the gas molecules will leave the solid surface more easily after the energy is increased.

Preferably, the casting is one of a seepage casting method, a centrifugal casting method, and an extrusion casting method.

Preferably, the method of applying the energy source is to apply ultrasonic waves or heat to the mold cavity or jacket by using an ultrasonic device and/or a heating device.

The method of heating to increase energy is one of the effective ways to increase the energy of gas molecules. The method for increasing the energy of the heating device to promote the adsorption of the gas can be used in the process of preparing the composite material by casting or sheath extrusion and is used for eliminating the gas adsorbed in a sheath cavity.

The ultrasonic wave as elastic mechanical vibration wave has the characteristic of large vibration acceleration of mass points in a propagation medium, and different mediums have obvious difference on absorption of the ultrasonic wave, wherein the absorption is the weakest in solid propagation, the second in liquid and the strongest in gas. Therefore, the ultrasonic wave can be used as an energy source to provide energy for the mold, the mold transfers the energy to the gas molecules adsorbed on the surface of the cavity of the mold, the energy of the gas molecules is lifted to break away from the constraint of van der Waals force and break away from the surface of the mold cavity, and the purpose of efficiently eliminating the gas adsorbed on the surface is achieved under the action of the vacuum pump. For example, when the squeeze casting method is used, ultrasonic waves can be used as an energy source to increase the energy of gas molecules adsorbed on the inner wall of the cavity, so that the gas adsorbed on the inner wall of the cavity can be rapidly eliminated.

When the vacuum pumping is carried out, the energy of gas adsorbed on the surface of the solid is improved by assisting the processed object with a heating device or an ultrasonic device, so that the purpose of efficiently eliminating the gas adsorbed on the surface of the solid is achieved. The method and the related device can be particularly applied to the methods for preparing advanced precise materials by an extrusion casting method, a centrifugal casting method, a seepage casting method and the like, and can also be used for efficiently eliminating adsorbed gas in a jacket in advance when a composite material is prepared by a jacket extrusion method.

Preferably, the heating mode is one or more of electric heating, liquid heating and gas heating.

Preferably, when the seepage casting method is adopted, a heating device is adopted to heat the cavity of the mold while vacuumizing, the temperature is 50-260 ℃, and the time is 5-45 min.

More preferably, when the seepage casting method is adopted, a heating device is adopted to heat the cavity of the mold in the vacuumizing process, the temperature is 75-260 ℃, and the time is 8-35 min.

Preferably, when the seepage casting method is adopted, the ultrasonic treatment is carried out on the die cavity while the vacuum pumping is carried out, the power capacity range of the ultrasonic transducer is 16-180 kW, and the treatment time is 5-40 min.

Preferably, when the seepage casting method is adopted, the mold cavity is simultaneously heated and ultrasonically treated in the vacuumizing process for 2-20 min, so that the vacuumizing time can be effectively reduced.

Preferably, when a centrifugal casting method is adopted, a heating device is adopted to heat the cavity of the mold while vacuumizing, the temperature is 80-180 ℃, and the time is 3-35 min.

More preferably, when the centrifugal casting method is adopted, a heating device is adopted to heat the cavity of the mold while vacuumizing, the temperature is 80-120 ℃, and the time is 3-15 min.

Preferably, when the centrifugal casting method is adopted, ultrasonic waves are adopted as an energy source while vacuumizing, the ultrasonic wave energy range is 11-600 kW, and the treatment time is 10-45 min.

More preferably, when the centrifugal casting method is adopted, ultrasonic waves are adopted as an energy source while vacuum pumping is carried out, the power capacity range of an ultrasonic transducer is 28-550 kW, and the ultrasonic treatment time is 8-30 min.

Preferably, when the extrusion casting method is adopted, the mould is subjected to ultrasonic treatment while vacuumizing, the ultrasonic energy is 5-450 kW, and the treatment time is 1-30 min.

More preferably, when the extrusion casting method is adopted, the kinetic energy of the gas adsorbed on the inner wall of the cavity of the mold is improved by adopting ultrasonic waves, the power capacity range of the ultrasonic transducer is 8-420 kW, and the ultrasonic treatment time is 1.5-25 min.

Preferably, when the extrusion casting method is adopted, the mold is subjected to pre-ultrasonic treatment 5-10 min before vacuumizing, so that a large amount of gas molecules are promoted to be separated from the inner wall of the mold, and the vacuumizing efficiency is improved in the vacuumizing process. And in the subsequent vacuumizing process, the ultrasonic wave is intermittently started or the ultrasonic wave is started in the whole process, the power capacity range of the ultrasonic transducer is 15-380 kW, and the ultrasonic treatment time is 1-20 min during vacuumizing. When the material is prepared by an extrusion casting method, ultrasonic waves are applied to improve the kinetic energy of gas adsorbed on the inner wall of a cavity of a die, and the specific pre-ultrasonic treatment time is related to the following two points: the complexity of the cavity of the mold, and the appearance, structure, quantity and the like of the second phase when the composite material is prepared.

Preferably, during the extrusion of the sheath, the mold cavity is heated by one of tube furnace heating, water bath heating and oil bath heating while vacuumizing is performed.

More preferably, when the sheath is extruded, if the outer diameter of the sheath is less than or equal to 20cm, the second phase in the sheath is a block and is made of metal material, one of the methods of heating by a tube furnace, heating by water bath and heating by oil bath is adopted to improve the kinetic energy absorbed in the gas in the sheath.

More preferably, when the jacket is extruded, if the diameter of the jacket is more than or equal to 20cm and the second phase in the jacket is a material with poor thermal conductivity, such as a ceramic phase, a heating device and ultrasonic waves are simultaneously adopted to improve the energy of gas molecules absorbed in the jacket, and the heating device is one of electric heating, liquid heating and gas heating.

Preferably, when the sheath is extruded, a heating device is adopted to heat the cavity of the die in the vacuumizing process, the temperature is 80-150 ℃, and the time is 15-150 min. When the jacket is large, for example, more than 20cm in diameter, and the interior is a poor thermally conductive material, such as ceramic particles, higher temperatures and longer heating times are generally used.

Preferably, when a large amount of granular or powder materials are filled in the sheath, in order to prevent the loss of the granules or powder in the vacuumizing process, the granules or powder need to be pre-vacuumized by a vacuum pump for 10-45 min at room temperature before being heated and vacuumized, and then degassing is performed according to the heating and vacuumizing requirements.

A device for efficiently eliminating gas adsorbed on a solid surface comprises a mold cavity or a sheath and an ultrasonic device and/or a heating device for applying energy to the gas adsorbed on the solid surface, wherein when the ultrasonic device is used as an energy source, an ultrasonic transducer vibrator is placed on the outer surface of the mold cavity or the sheath, or when the heating device is used, the mold cavity or the sheath is placed in the heating device, or the mold is made to be hollow, and liquid heating is introduced into the middle of the mold cavity or the sheath.

The invention also protects the application of the method in eliminating gas adsorbed on the surface of the solid when the device is manufactured in a vacuum environment.

Preferably, the application is the elimination of gas adsorption from solid surfaces when manufacturing precision devices in a vacuum environment or using the devices in the field of the tip.

Compared with the prior art, the invention has the beneficial effects that:

the sample prepared by advanced casting methods such as an extrusion casting method, a seepage casting method, a centrifugal casting method and the like has the problem that the micropores appear in the sample and the bubbling, internal cracking and the like appearing after the sheath is extruded are not related apparently, and the problems are all caused by gas adsorbed on the surface of the solid. In order to eliminate gas adsorbed on the solid surface efficiently, the invention improves the kinetic energy of the gas and the energy of gas molecules is improved by applying an energy source to the gas adsorbed on the solid surface, so that the constraint of Van der Waals force can be broken away, the gas can be separated from the surface of a mold cavity or a sheath, the gas in the mold cavity or the sheath can be eliminated completely under the action of a vacuum pump, and the purpose of efficiently eliminating the gas adsorbed on the surface is achieved. The method of the invention can be applied to common manufacturing process, has good effect when being applied to the manufacturing of extremely complex precision devices, and can be applied to the advanced manufacturing technical fields of extrusion casting method, seepage casting method, centrifugal casting method and the like, can also be applied to the fields of sheath extrusion method for preparing composite materials and the like, and can also be applied to other related fields for eliminating gas adsorbed on the surface of solid or processes needing to be operated in vacuum.

Drawings

FIG. 1 is a schematic view of adsorption of gas molecules on a solid surface under microscopic conditions.

FIG. 2 is a schematic diagram of adsorption of gas molecules on a solid surface under microscopic conditions with an external energy source.

FIG. 3 is a cross-section of a composite sample prepared by infiltration casting after ultrasonic treatment of the chamber of example 1.

FIG. 4 is a schematic diagram of the vacuum pumping process of the jacket in example 2, wherein a heating furnace is used as an external energy source.

FIG. 5 is a schematic diagram of the application of ultrasonic waves as an external energy source in the vacuum-pumping process of the jacket in example 2.

FIG. 6 is a graph showing holes in a long fiber composite prepared by percolation in comparative example 1.

Fig. 7 shows the interfacial cracking of a jacket extruded oriented long fiber composite of example 2.

Detailed Description

The present invention will be further described with reference to specific embodiments, but the present invention is not limited to the examples in any way. The starting reagents employed in the examples of the present invention are, unless otherwise specified, those that are conventionally purchased.

Example 1

A method for eliminating gas adsorbed on solid surface efficiently applies an energy source to gas adsorbed on solid surface to improve kinetic energy of the gas by applying an ultrasonic wave to a die cavity while vacuumizing the die cavity in the process of preparing a long fiber oriented composite material by a seepage casting method, thereby eliminating gas molecules adsorbed in the die cavity efficiently, and the specific method is as follows:

considering that the addition amount of long fibers serving as a second phase of the composite material is large and the introduced surface area is large, firstly carrying out pre-ultrasonic treatment on a chamber for 4min, then starting a vacuum-pumping system for vacuumizing for 40min, and intermittently starting ultrasonic treatment in the vacuumizing process, wherein the ultrasonic power is 18kW, and the ultrasonic treatment is stopped for 5min every 3 min. And after the vacuum pumping is finished, melting the prepared alloy block into alloy liquid, further infiltrating the alloy liquid into gaps of the oriented long fibers, and after the infiltration is finished, rapidly cooling the alloy liquid and the oriented long fibers to obtain the oriented long fiber composite material.

The cross-section of the composite material prepared by the above method is shown in fig. 3, from which it can be seen that no voids are present at the junction of the second phase long fibers and the matrix. This shows that the use of ultrasonic waves as an energy source to increase the energy of the gas adsorbed on the solid surface during the vacuum-pumping process is very effective for efficiently eliminating the gas adsorbed on the solid surface.

Example 2

Before the sheath is extruded, the sheath needs to be vacuumized to eliminate gas in the sheath, and in order to improve degassing efficiency, the kinetic energy of the gas adsorbed on the solid surface in the sheath is improved by means of an external energy source while the sheath is vacuumized, so that the gas is enabled to be separated from the solid surface, and gas molecules adsorbed in a cavity of the sheath are eliminated efficiently. The schematic diagram of the heating furnace used as the external energy source in the sheath vacuumizing process is shown in fig. 4, and the schematic diagram of the ultrasonic wave used as the external energy source in the sheath vacuumizing process is shown in fig. 5. In this embodiment, in the vacuum pumping process, a specific method for heating the sheath by using the heating furnace is as follows:

a plurality of metal rods with the diameter of 0.5cm are arranged in the sheath, and in the process of vacuumizing, the influence of the heating temperature and the vacuumizing time on the vacuum degree in the sheath is researched through comparison of readings of a vacuum gauge, in the embodiment, the heating mode of the sheath is liquid heating, and the obtained data are shown in table 1.

TABLE 1 comparison of vacuum gauge readings at different times of jacket heating or not

And according to the normal operation flow, after the sheath is vacuumized for 40min, sealing the sheath, and processing at the next stage. As can be seen from the comparison in Table 1, when the jacket was heated, the reading of the vacuum gauge was higher when the jacket was heated than when it was not heated (temperature was 20 ℃ C.) only at 10min, because the heating of the jacket continuously released the gas molecules adsorbed on the surface of the metal rod into the jacket, resulting in an increase in the reading displayed by the vacuum gauge; from 20min onwards, the vacuum gauge reading when the jacket was heated was lower than when it was not heated, which indicates that the gas molecules adsorbed in the jacket in the heated state broke loose the van der waals force bound and dissipated in the jacket and rapidly pumped away by the molecular pump, resulting in a decrease in vacuum, while the gas molecules adsorbed in the jacket in the unheated state broke loose the van der waals force less efficiently and therefore continuously, which results in a higher vacuum reading in the unheated state. At 30min and 40min, the reading of the vacuum gauge in the heating state is always stabilized at the limit reading position of the vacuum pump, which indicates that the gas molecules adsorbed in the sheath are basically removed, while the reading of the vacuum gauge in the non-heating state indicates that the vacuum reading is higher than the limit vacuum degree of the vacuum pump after the vacuum pumping treatment for 40min, which indicates that the gas molecules adsorbed in the sheath are still continuously separated from the solid surface, so that the reading of the vacuum gauge is obviously higher than the limit value of the vacuum pump.

Example 3

At present, most of block amorphous alloy materials and devices applied to electronic products such as mobile phones and the like are manufactured by adopting an extrusion casting method, and the conventional process comprises the following steps: and (3) pre-vacuumizing the cavity of the mold, and then quickly injecting the alloy liquid into the cavity of the mold to be solidified to obtain the required amorphous alloy piece. At present, micropores in a block amorphous alloy part prepared by adopting an extrusion casting method are one of the problems concerned by the industry, and especially the micropores in the amorphous alloy part with a complex configuration and a thin wall are more serious.

A method for eliminating gas adsorbed on solid surface efficiently applies ultrasonic wave to the cavity of mould while vacuumizing it in extruding casting process, and applies energy to the gas adsorbed on solid surface to increase its kinetic energy and eliminate the gas adsorbed on solid surface. The method is characterized in that a mould for manufacturing the amorphous alloy piece with thin wall and complex configuration is taken as a research object, the vacuumizing time of a cavity of the mould is set to be 5min, and the influence of whether the mould is subjected to ultrasonic treatment or not in the vacuumizing process on the reading of a vacuum gauge is contrastingly researched, and the result is shown in table 2.

TABLE 2 influence of whether ultrasonic treatment during evacuation has on the reading of the vacuum gauge

As can be seen from Table 2, the vacuum reading of the mold cavity at 5min was 4.4X 10 when the mold was not treated with ultrasound during the evacuation process^-1Pa, limit value reached when the vacuum pump was evacuated, which indicates that the chamber was evacuated for 5min continuouslyA small amount of gas remains in the chamber. When the ultrasonic treatment is carried out on the die in the vacuumizing process, the reading of the vacuum gauge reaches the limit value of the vacuum pump at the 2.5min, and the reading is maintained until the 5min, which shows that the ultrasonic treatment is carried out on the die in the vacuumizing process can effectively eliminate residual gas in the die cavity in a short time, the removing effect is more obvious, the time is shorter, and the ultrasonic treatment has very important significance for ensuring the industrial production efficiency.

Example 4

A method for eliminating gas adsorbed on solid surface efficiently applies energy source to gas adsorbed on solid surface to improve kinetic energy of the gas by heating a sheath chamber while vacuumizing the sheath chamber in the sheath extrusion process, thereby eliminating gas molecules adsorbed in a mold chamber efficiently, and the specific method is as follows:

after a large amount of powder is filled in the sheath, the sheath is vacuumized, and in the vacuumizing process, referring to example 2, the sheath is heated to 120 ℃ in an electric heating mode. Compared with a metal rod, the powder has a higher specific surface area on one hand, and the heat conductivity of the powder is obviously lower than that of the metal rod on the other hand. These two aspects determine that the effect of heating during evacuation of the powder in the sheath is inferior to that of evacuation of the metal rod in example 2. In order to increase the efficiency of the evacuation, the jacket is heated and simultaneously treated with ultrasound. In order to prevent the powder from being pumped out of the sheath along with the gas in the vacuumizing process, the following procedures are adopted to pump the vacuum in the sheath: (1) pre-pumping gas in the sheath for 30min at room temperature with a vacuum pump until the vacuum degree in the sheath is maintained at 3.5 × 10¹When Pa is needed, the next operation can be carried out, namely, the sheath is heated and ultrasonically treated while vacuumizing is carried out; (2) keeping the vacuum pump in an open state, and starting the external energy source.

The comparative data in table 3 show that the 120 ℃ + auxiliary ultrasonic wave significantly improves the effect of vacuumizing the sheath during the vacuumizing process. In the process of vacuumizing, ultrasonic treatment and heating have very important influence on the elimination effect of adsorbed gas in the sheath.

TABLE 3 comparison of vacuum gauge readings at different times with or without additional sonication

Comparative example 1

This example is a comparison of example 1. Still taking the metal-based directional composite material prepared by the seepage casting method in the laboratory as an example, the parameters of the sample such as the vacuum-pumping time, the heating temperature, the heat preservation time and the like are completely the same as those in the example 1 except that the ultrasonic treatment is not added. The cross section of the sample prepared this time is shown in fig. 6, and it can be seen from the figure that even though the mold cavity is vacuumized, the specific surface area introduced is high, the amount of adsorbed gas is large, so that more than one hole appears on the composite material interface, and the holes lead to the deterioration of the binding property between the matrix and the second phase of the composite material, thereby adversely affecting the mechanical properties thereof.

Comparison between comparative example 1 and example 1 shows that in the process of vacuum pumping by using a vacuum pump, the auxiliary ultrasonic treatment helps to efficiently eliminate gas adsorbed on the solid surface, and the problem of sample performance reduction caused by residual adsorbed gas is avoided.

Comparative example 2

This comparative example is a comparison of example 2. According to the comparative example, a certain oriented long fiber composite material prepared by sheath extrusion is vacuumized for 40min at room temperature, the sheath is sealed, and a composite bar with a normal appearance is obtained after hot extrusion. However, a certain amount of gas remained in the envelope (the vacuum gauge reading was 9.7X 10 before sealing the envelope)^-1Pa), and frequent wire breakage occurs in the process of drawing the extruded composite bar by multiple passes.

When the sample was sampled and analyzed along the axial direction of the wire, after removing the coating layer (so-called coating layer, i.e., sheath portion) on the surface of the sample, the interior of the composite material was found to be cracked along the surface of the long fiber, and as shown in FIG. 7, the sample was completely discarded. The phenomenon is mainly caused by gas molecules adsorbed on the surface of the long fiber, and in the processes of sheath extrusion and composite bar drawing, the gas molecules are gathered at the interface of the long fiber and the matrix to form a layer of gas film, and the gas film flows along with external force to cause interface cracking.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for eliminating gas adsorbed on solid surface with high efficiency is characterized in that during casting and/or extrusion of a sheath, energy is applied to the gas adsorbed on the solid surface while a cavity of a mold or the sheath is vacuumized to increase kinetic energy of the gas adsorbed on the solid surface and eliminate the gas adsorbed on the solid surface.

2. The method of claim 1, wherein the casting is one of a seepage casting process, a centrifugal casting process, and an extrusion casting process.

3. A method according to claim 1 or 2, wherein the energy is applied by applying ultrasound or heat to the mould cavity or sheath using an ultrasound device and/or a heating device.

4. The method according to claim 3, wherein the heating mode is one or more of electric heating, liquid heating and gas heating.

5. The method according to claim 3, wherein when the infiltration casting method is adopted, the mold cavity is heated by a heating device at 50-260 ℃ for 5-45 min while vacuumizing.

6. The method of claim 3, wherein the centrifugal casting method is performed by heating the mold cavity by a heating device at 80-180 ℃ for 3-35 min while vacuumizing.

7. The method according to claim 3, wherein when the infiltration casting method or the centrifugal casting method is adopted, ultrasonic waves are adopted as an energy source while vacuum pumping, the ultrasonic wave energy range is 11-600 kW, and the treatment time is 10-45 min.

8. The method of claim 3, wherein the extrusion casting method is adopted, the vacuum pumping is performed, the ultrasonic energy is 5-450 kW, and the processing time is 1-30 min.

9. A device for efficiently eliminating gas adsorbed on a solid surface is characterized by comprising a mold cavity or a sheath and an ultrasonic device and/or a heating device for applying energy to the gas adsorbed on the solid surface, wherein when the ultrasonic device is used as an energy source, an ultrasonic transducer vibrator is placed on the outer surface of the mold cavity or the sheath, or when the heating device is used, the mold cavity or the sheath is placed in the heating device, or the mold is made to be hollow, and the middle of the mold is filled with heating liquid.

10. Use of the method of any one of claims 1 to 8 for eliminating gas adsorption on a solid surface during the manufacture of a device in a vacuum environment.